Salad oils and method of making them



7 Y, i r 7 SALAD 0115 AND METHOD OF lt iAi'GNG Tern. 't i Frederic .i. Baur, Qineinnati, Ohio, assignor to The i roeter & Gamble Company, Qincinnati, Ohio, a corporation of Ohio No Drawing. Fiierl l t Jar. 2'7, H62, er. No. 182,956

12 Claims. (ill. 99-118) This invention relates to improved salad oils. More particularly, it relates to oils which can be stored at relatively low temperatures for extended periods of time without clouding, and which are capable of being used in preparing mayonnaise emulsions which themselves can be stored at low temperatures.

Oils which are suitable for salad use are frequently stored in refrigerators. The cooling of such oils to temperatures encountered in refrigerators, such as about 40 to 50 F., results in the deposition of crystalline material, usually solid triglycerides, from the oil. This material may appear in the form of a cloud, or as a group of crystals, and is considered objectionable by the housewife. The tendency to form solid glycerides in oils also adversely affects the suitability of the oil for use in mayonnaise emulsions. Mayonnaise emulsions prepared from such oils tend to be unstable at low temperatures and are more easily broken.

Frequently it is desirable to hydrogenate natural vegetable oils, such as soybean oil, in order to improve their oxidative stability. This hydrogenation will tend to raise the melting point and to produce components of decreased solubility in the oils, causing them to have the undesirable properties listed hereinbefore.

A large proportion of the undesirable material can be removed from oils by the process known as Winterizing in which the oils are carefully cooled to low temperatures for extended periods of time to permit precipitation of solid material. Such solids can then be removed by pressing or other separation procedures. However, not all of the high-melting solid material is removed from the oils by this processing, and the oils still tend to cloud when stored for extended periods of time at low temperatures.

It has now been found that under the present invention the time for storage at low temperatures without clouding can be greatly extended for salad oils.

Accordingly, it is an object of this invention to provide an improved salad oil.

A further object of this invention is to provide a salad oil which will remain free from clouding or crystal formation for longer periods of time than will oils which have been merely treated by conventional Winterizing techi niques.

Other objects and advantageous features will be apparent from the following detailed description.

A standard testing procedure for salad oils involves holding the oil at a temperature of 30 F. until a cloud forms in the oil. As used herein, the term chill test is intended to define the length of time, after cooling the oil to 30 F. (unless some other temperature is specified), until such a cloud forms.

In general, oils of this invention comprise aclear base salad oil containing dissolved therein at least 0.001%, by weight, of fatty acid ester of dextrin. should be esterified with an average, per glucose unit, of from about /2 to 2 mols of saturated fatty acid having from 14 to 22 carbon atoms. The balance of the fatty acids are selected from the group consisting of fatty acids having from 2 to 12 carbon atoms or unsaturated fatty acids having from 14 to 22 carbon atoms. The ester must have an average of not more than 1 /2 unesterified hydroxyl groups per glucose unit.

It will be appreciated that dextrin ester used in the practice of this invention usually will be a reaction prod- The dextrin ice not containing a mixture of different esters. Also, the individual glucose units of the dextrin may not necessarily be esterified with identical combinations of fatty acids. For this reason, the invention is defined in terms of average fatty acid proportions associated with the glucose moiety of the dextrin ester.

For example, a suitable ester for this invention is dextrin esterified with an average of from 6 to 2 palmitic acid groups per glucose unit. Other long-chain saturated fatty acid groups such as those of myristic, stearic, ar-

achidic, or behenic acids, and mixtures thereof, can be present in the ester in place of part or all of the palmitic acid groups. Since the dextrin esters of this invention must contain an average of not more than about one and one-half free hydroxyl groups per glucose unit, the dextrin'can be esterified additionally with short-chain fatty acids such as acetic, propionic, butyric, caproic, caprylic, capric, lauric, and/or lauroleic acids, or with long-chain unsaturated fatty acids such as myristoleic, palmitoleic, oieic, linoleic, linolenic, gadoleic, arachidonic, erucic, clup anodonic, elaidic, and/ or brassidic acids.

A Wide'variety of oils can be used as base salad oils in the practice of this invention either individually or as mixtures of oils. Included among suitable oils are the socalled natural salad oils such as olive oil, sunflowerseed oil, safiiower oil, and sesame oil. Oils such as cottonseed oil and corn oil must be given a preliminary Winterizing, dewaxing, or other treatment to remove the higher melting solids to form a good base salad oil. Other oils, such as soybean oil, may require some hydrogenation to prevent rancidity with prolonged storage, and the highermelting glycerides formed during this hydrogenation treatment should be removed. Base salad oils can also be formed by directed, low-temperature interest'erification of animal and vegetable fatty materials, followed by removal of higher-melting glycerides formed during the reaction (US. Patent 2,442,532, issued June 1, 1948, to E. W. Eckey). Another group of oils includes those in which one or more short-chain fatty acids replace the longer-chain fatty acids present in natural triglyceride oils. Other basesalad oils will suggest themselves to those skilled in the art, provided they have a suitable chill test as hereinbefore defined. As used herein the term base salad oil is intended to include any salad oil which will not form solids immediately when cooled to The esters of dextrin suitable for use in this invention can be prepared by a variety of methods. For example, dextrin can be reacted with mixtures of anhydrides of suitable fatty acids in the presence of suitable catalysts. Another method comprises the reaction of dextrin with acid chlorides. It is to be understood, however, that the invention is not to be limited to any specific method of preparation of the dex'trin ester.

The ester and the base salad oil can be mixed together in any convenient manner. For example, ester in liquid form or melted ester can be mixed with the oil. If the ester is in solid form, it can be dissolved in the oil, although it may be desirable to heat the oil or the mixture of oil and ester to facilitate solution. It is to be kept in mind, however, that in all cases the resulting product is merely a physical mixture and there isno apparent chemical reaction between the ester and the oil.

The following examples will serve to further illustrate the invention. a

Example I 0.1% of an acetyl-palmitoyl dextrin was dissolved in a winterized cottonseed oil having a chill test of 4 /2 hours. The dextrin was esterified with an average of about 1 /2 acetic acid groups and 1 /2 palmitic acid groups per glucose unit, The solution was held at 30 in which any of the various shortand long-chain fatty acids as hereinbefore described replace the acetic acid and palmitic acid.

Example II Refined and bleached cottonseed oil was winterized by storing it at 40 F. for 5 days and then removing the crystals which had formed by vacuum filtration. The dextrin ester of Example I was added to this oil at levels of 0.02% and 0.005%, by weight. The mixtures were heated to 275 F. with continuous stirring. The heated materials were placed in 4-02. bottles, which were then corked and sealed with parafiin. The bottles were placed in an ice bath, together with bottles containing the oil without additives, and inspected at regular intervals. The following chill test results were noted.

' Chill test (days Amount of ester (percent by weight) at 32 F.)

None 2 0.005

at a level of 0.005%, by weight, to refined and bleached soybean oil which had been hydrogenated to an iodine value of 107 and then winterized. The oil containing the additive had a chill test at 32 F. of greater than 7 days,

while the oil without additive had a chill test of only 4 days.

Example IV Soybean oil was slightly hydrogenated and then winterized to remove high-melting solids. Theproduct had a chill test of 13 /2 hours. Dextrin was esterified with acids from .a mixture of 80% soybean oil and cottonseed oil which had been hydrogenated to an iodine value of about 70. The fatty acids comprised about 8.4% palmitic, 8.4% stearic, 75.0% monoenoic, 7.9% dienoic, and 0.3% trienoic acids. The ester was substantially completely esterified. 0.1% of this dextrin ester was dissolved in the winterized soybean oil. When the oil was held at F. it was found to have a chill test of more than 42 hours. The addition to similar oil of dextrin esterified with other combinations of saturated and unsaturated long-chain fatty acids, as hereinbefore defined, will also provide improved chill tests.

Example V A salad oil was formed by randomly interesterifying a mixture of 246 pounds of cottonseed oil and 246 pounds of triacetin. Excess triacetin was removed by deodorizing the interesterified product. This oil had a chill test of less than 1 /2 hours. 0.1% of the dextrin ester of Example I was dissolved in this oil, and its chill test at 30 F. was found to be greater than 42 hours. Similar results can be obtained by adding the ester to salad oils formed by the random interesterification of tripropionin, tributyrin, tricaproin, or tricaprylin with cottonseed or other vegetable oils.

Example VI Example VII Refined and bleached cottonseed oil was winterized. Testing samples were made by adding to portions of the oil 0.01 and 0.05 percent, by weight, of a dextrin dipalmitate, having an average of 2 palrnitic acid groups per glucose unit. The two portions and a third, to which no ester had been added, were heated to completely dissolve all crystal nuclei and then placed in a room having a constant temperature of 40 F. The time of appearance of the first cloud in each of the samples was noted. For the oil without ester this time was less than 114 hours. In each of the oils containing the dextrin ester, the time was approximately 216 hours.

Example VIII Refined and bleached cottonseed oil was heated to a temperature of about to 140 F. to destroy all crystal nuclei. The oil was winterized by holding it at 40 F. for at least 48 hours to permit solid glycerides to form.

V The oil was then filtered through a plate and frame filter chain acid. The average compositions of these esters' were as follows:

Ratio: Acetic Acid/ Palmitio Acid Percent Unesterified l Ester A 1.2/1.0

Less than 10%. Ester B 1.32/1.0 Less than 2%. Ester C 1.45/10 Less than 5%.

Varying amounts of the dextrin esters were added to 200 g. samples of these winterized oils, and heated to C. to drive ofl? moisture and to destroy all crystal nuclei. The oils were then allowed to cool to 30 C., and sealed in glass bottles. An ice water mixture was prepared, and the bottles were completely immersed. The bottles were examined at intervals and the time of first appearance of grains of crystals or of a cloud was noted.

The following data were observed:

Amount Chill Test Ester (percent by Oil (32 F.) weight) (Hours) (Control) Winterized soybean. 26

(Control) 14 Example IX Amount of ester Chill test (Percent by weight (Hours) Example X Cottonseed oil was refined, bleached, deodorized, and winterized to form a material having a chill test not exceeding 24 hours. In this was dissolved 0.1% of mono-acetyl-dipalmitoyl dextrin containing, per glucose unit, an average of about 2 palmitic acid radicals and about one acetic acid radical. The chill test of the oil was 6 /2 days.

Although it is desired not be bound by any theory, it is believed that inhibition of the formation of crystalline material in oil is accomplished by selecting a ma terial which, at the temperature at which protection is disired, will be substantially dissolved in the oil, but the amount of inhibitor added should be at a level not far below that at which precipitation of the inhibiting material in the oil will occur. It is believed that the inhibitor acts by being adsorbed on the invisible crystal nuclei of the higher-melting components of the substrate oil so that further crystallization of these components is greatly retarded. Materials having strong tendencies to be adsorbed can be added at lower levels than materials with weaker adsorptive tendencies.

A proper balance is required for the optimum inhibition of a systema balance between solution tendency as particularly promoted by unsaturated (or low molecular weight) chains on the ester and adsorptive tendency as promoted by saturated chains. It would be presumed that since trans-unsaturated chains are intermediate be tween cis-unsaturated and saturated chains in their usual effect on melting level, they would also be intermediate in their effect on inhibition action. Experimental work has indicated, however, that cisand trans-chains appear to be comparable in their effect on inhibition power.

If too large an amount of inhibitor is present, it will precipitate out of solution and possibly even promote crystallization of high-melting solids in the oil. Too small an amount of inhibitor, of course, will be relatively ineffective. Thus, dextrin completely esterified with longchain saturated fatty acids will be too insoluble to inhibit efiectively crystallization of high-melting glycerides in oil at 30 F. However, dextrin esterfied partly with longchain saturated fatty acids and partly with unsaturated long-chain fatty acids or with short-chain fatty acids can generally be used in sufficient concentrations without precipitating out, and will provide very satisfactory crystal inhibition. Amounts of ester in excess of about 0.5%, by weight, are unnecessary as affording no significant added improvement of the oil.

This is a continuation-impart of application Serial No. 104,003, filed April 19, 1961, now abandoned.

What is claimed is:

1. A clear glyceride salad oil having superior resistance to deposition of high-melting solids and comprising 6 a base salad oil having dissolved therein at least about 0.001%, by weight, of fatty acid ester of dextrin, said deXtrin being esterfied with an average, per glucose unit, of from about /2 to 2 mols of saturated fatty acid having from 14 to 22 carbon atoms, the balance of the fatty acids being selected from the group consisting of fatty acids having from 2 to 12 carbon atoms and unsaturated fatty acids having from 14 to 22 carbon atoms, said ester having an average of not more than 1 /2 unesterified hydroxyl groups per glucose unit.

2. A salad oil according to claim 1 wherein the fatty acids comprise acetic and palmitic acids.

3. A salad oil according to claim 1 wherein the fatty acids comprise palmitic, istearic, monoenoic, dienoic, and trienoic acids.

4. A salad oil according to claim 1 wherein the ester is dextrin dipalmitate.

5. A salad oil according to claim 1 wherein the ester is monoacetyl dipalmitoyl dextrin.

6. A salad oil according to claim 1 wherein the ester is monopalmitoyl diacetyl dextrin.

7. The method of retarding the deposition of highmelting solids from salad oils which comprises dissolving in a clear base salad oil at least 0.001%, by weight, of fatty acid ester of dextrin, said dextrin being esterified with an average, per glucose unit, of from about V2 to 2 mols of saturated fatty acid having from 14 to 22 carbon atoms, the balance of the fatty acids being selected from the group consisting of fatty acids having from 2 to 12 carbon atoms and unsaturated fatty acids having from 14 to 22 carbon atoms, said ester having an average of not more than 1% unesterified hydroxyl groups per glucose unit.

8. The method according to-claim 7 wherein the fatty acids comprise acetic and palmitic acids.

9. The method according to claim 7 wherein the fatty acids comprise palmitic, stearic, monoenoic, dieuoic, and trienoic acids.

10. The method according to claim 7 wherein the ester is dextrin dipalmitate.

11. The method according to claim 7 wherein the ester is monoacetyl-dipalmitoyl dextrin.

12. The method according to claim 7 wherein the ester is monop almitoyl-diacetyl dextn'n.

References Cited in the file of this patent UNITED STATES PATENTS 2,223,558 Epstein Dec. 3, 1940 2,266,591 Eckey et al. Dec. 16, 1941 2,422,633 Petersen June 17, 1947 

1. A CLEAR GLYCERIDE SALAD OIL HAVING SUPERIOR RESISTANCE TO DEPOSITION OF HIGH-MELTING SOLIDS AND COMPRISING A BASE SALAD OIL HAVING DISSOLVED THEREIN AT LEAST ABOUT 0.001%, BY WEIGHT, OF FATTY ACID ESTER OF DEXTRIN, SAID DEXTRIN BEING ESTERFIED WITH AN AVERAGE, PER GLUCOSE UNIT, OF FROM ABOUT 1/2 TO 2 MOLS OF SATURATED FATTY ACID HAVING FROM 14 TO 22 CARBON ATOMS, THE BALANCE OF THE FATTY ACIDS BEING SELECTED FROM THE GROUP CONSISTING OF FATTY ACIDS HAVING FROM 2 TO 12 CARBON ATOMS AND UNSATURATED FATTY ACIDS HAVING FROM 14 TO 22 CARBON ATOMS, SAID ESTER HAVING AN AVERAGE OF NOT MORE THAN 1 1/2 UNESTERFIED HYDROXYL GROUPS PER GLUCOSE UNIT. 